Fuel burner



Dec. 6, 1966 F. F. MOENCH ETAL 3,289,728

FUEL BURNER Filed April 50, 1965 INVENTORS. Frank E Moench Carl W. Johnson BY ATTORNEYS United States Patent 3,28,728 FUEL BURNER Frank F. Moench, Denver, Colo. (314 S. Salem St, Aurora, Colo.), and Carl W. Johnson, 3886 Chase Court, Boulder, Colo.

Filed Apr. 30, 1965, Ser. No. 452,307 Claims. (Cl. 15879) This invention relates to improvements in burners and more particularly to improvements in liquefied petroleum gas. burners for high temperature applications.

The present invention provides an improved burner apparatus, which is a simple, highly etficient burner. The device of the present invention burns liquefied petroleum gas at a higher B.t.u. output in an efiicient, highly'effective manner.

It is, accordingly, an object of my invention to provide a simple, durable and a highly efficient burner for liquefied petroleum gas.

Another object of the invention is to provide a burner for liquefied petroleum gas which insures complete vaporization of the liquid for efficient and effective burning at higher flow rates of fuel, thus producing higher B.t.u. output at maximum flame temperature.

Still another object of the invention is to provide an efficient burner for liquefied petroleum gas which provides a multistage nozzle and a venturi effect for secondary air for burner flame.

Other objects and advantages reside in the novel details of construction and the novel combinations and arrangements of parts, all of which will be described in the course of the following description.

The present invention may be understood by referring to the following description and appended illustrations in which the several views having like parts bear similar reference numerals.

In the drawings:

FIG. 1 is a partial cross-sectional view of a burner arrangement according to the invention; and

FIG. 2 is an end elevation of the burner of FIG. 1.

In the device selected for illustration, a tube or pipe 1 is Welded into a welded elbow fitting 2. On the opposite side of the elbow is welded a fuel heating coil 3 of tubular material, part of which covers a blast tube 4. The opposite end 5 pf the coil 3 is welded into another elbow 6 which has a short nipple 7 welded to the other side. A reducing nipple 3 is welded with a pressure proof seal over the nipple 7 adjacent the end of the elbow 6 and an expansion tube or chamber 9 is welded onto the large end of the reducing nipple. A similar reducing nipple 1d is welded to the opposite end of tube 9 and the end of a U-shaped tube 11 is welded into the small end of the reducing nipple with its opening extending into the interior of the reducing nipple and spaced above the bottom of the expansion chamber 9.

A spray nozzle 12 is threadedly afixed to the end of the nipple 7 internally of the reducing nipple 8 and is provided with a plurality of small orifices 14, having a total cross-sectional area less than the cross-sectional area of the pipe of the coil, which are directed substantially axially along the tube 9. A multistage burner nozzle 15 is positioned on the free end of the U-shaped tube 11 and is spaced from but directed into the blast tube 4. The nozzle has a restricted orifice 18 through which the fuel must pass. This creates a high velocity fuel stream into chamber 20 which is provided with lateral openings for the inspiration of primary air. This mixture of air and gas passes into outlet chamber 16 which inspires additional air into the stream through lateral openings 17. These stages create a laminar flow which sucks or aspirates additional air in the high velocity stream.

3,28%,728 Patented Dec. 6, 19556 The blast tube 4 is held in position by braces 21 at the top, which is welded between the pipe 1 and the blast tube, and a brace '22 which is welded to the bottom of the blast tube and onto the tube 9. The opposite end of the blast tube is supported by the heater coil. A hex nut 23 is Welded to the bottom of the tube 9 to provide a foot for supporting the burner where desired.

The burner is arranged to be attached, through pipe 1, to a source of liquefied petroleum gas under pressure. The fuel passes through the heating coil and is sprayed into the expansion chamber and subsequently into the nozzle 15. The expansion chamber permits a higher rate of fuel flow through the unit as it gives the liquid fuel a chance to completely expand and vaporize prior to leaving the chamber. The liquid fuel passing through the coils picks up scavenged heat so that the fuel is hot as it is sprayed into the expansion chamber. The expansion chamber provides an intermediate stage for the fuel durin g the transition from liquid to vapor. The expansion chamber permits a fast warm-up without spraying liquid fuel through the nozzle. The vapor from the nozzle is directed into the blast tube, to the heating coil and ignited. The flame then passes out the opening in the coil and in the desired direction.

The nozzle is positioned adjacent to, but spaced from the blast tube 4-, a distance that contains the fireball within the coils. If the nozzle is spaced too far away from the tube, the initial fireball is located between the nozzle and the coils so that the flame burns out the blast tube. The distance from the nozzle to the blast tube is determined at time of manufacture, during testing of each burner. The passage of fuel through the coils acts as a coolant for the coils, i.e., the higher the flow rate (higher B.t.u. output), the more heat is absorbed by the fuel and keeps the coils from burning out. The blast tube or sleeve provides a tunnel effect and the high velocity of the gases from the nozzle draws in more air (secondary air) into the tube for burning. With combustion, the gases expand, increasing in volume and the velocity through the tube and coils, increasing the air drawn into the tube.

By using a /s coil pipe for the device of FIG. 3 a 2,000,000 Btu. per hour burner is provided. In this instance a 2" diameter expansion tube is provided and the outlet from the expansion tube is also pipe. Higher outputs require more coil absorption surface, hence a longer coil is required. It is thus seen that the burners are compact, economical and yet produce high efficiency in vaporizing all of the liquid passing through the burner nozzle for eflicient and effective combustion.

While the device has been illustrated with reference to particular embodiments, there is no intention to limit the spirit or the scope of the invention so set forth except as defined in the following claims.

We claim:

l. A burner assembly for liquefied petroleum gas com prising a line for attaching a source of supply of liquid petroleum gas, a coil of conduit connected to said line and provided with a passage centerwise therethrough, a blast tube at least partially telescoped in said coil, a burner nozzle to direct the flame through said blast tube and said coil, an expansion chamber interconnecting said coil and said burner nozzle, and an expansion nozzle internally of said expansion chamber connected to said conduit provid ing initial expansion of liquefied petroleum gas passing therethrou'gh.

2. A burner assembly according to claim 1 wherein said expansion nozzle includes a plurality of small orifices directed into said expansion chamber.

3. A burner assembly for liquefied petroleum gas comprising a line for attaching a source of a supply of liquid petroleum gas, a portion of said line being formed into a coil and there being a passage through said coil, a blast tube at least partially te-lescoped in said coil, a burner nozzle directed through said blast tube and said coil, an expansion chamber interconnected to said coil and said nozzle and mounted adjacent thereto, and an expansion nozzle internally of said expansion chamber connected to said line providing initial expansion of liquefied petroleum gas passing therethrough.

4. A burner assembly for liquefied petroleum gas comprising a line for attaching a source of a supply of liquid petroleum gas, a coil of tubular conduit connected to said line and provided with a passage centerwise thereof, a blast tube at least partially telescoped in said coil, a burner nozzle arranged to pass fuel for burning through said blast tube and said coil, an expansion chamber arranged adjacent said blast tube and coil interconnected to said coil at one end and said nozzle from itsoutlet, said expansion chamber having an outlet at a point spaced above the lowermost wall portion of said chamber in horizontal position so as to prevent passage of liquid from said chamber to said nozzle, and an expansion nozzle internally of said expansion chamber connected to said conduit providing initial expansion of liquefied petroleum gas passing therethrongh.

5. A burner nozzle for vaporized liquefied petroleum gas comprising a body having a passage therethrough for connection to a source of supply of liquefied petroleum gas, a constriction in said passage between the ends thereof forming a venturi section, a plurality of holes extending through said body laterally of said passage and connected with said passage at said constriction for drawing air into the stream of gas passing therethrough, and a plurality of lateral holes in said body beyond said constricted section for drawing in additional air on passage of gas through said nozzle.

References Cited by the Examiner UNITED STATES PATENTS 1,373,511 4/1921 Kramer 158-71 1,524,832 2/1925 McCoy 158-79 X 1,687,328 10/1928 DElia 158-54 2,341,380 2/1944 James 158-53 2,467,450 4/ 1949 Wollner 158-79 FREDERICK L. MATTESON, JR., Primary Examiner.

R. A. DUA, Assistant Examiner. 

1. A BURNER ASSEMBLY FOR LIQUEFIED PETROLEUM GAS COMPRISING A LINE FOR ATTACHING A SOURCE OF SUPPLY OF LIQUID PETROLEUM GAS, A COIL OF CONDUIT CONNECTED TO SAID LINE AND PROVIDED WITH A PASSAGE CENTERWISE THERETHROUGH, A BLAST TUBE AT LEAST PARTIALLY TELESCOPED IN SAID COIL, A BURNER NOZZLE TO DIRECT THE FLAME THROUGH SAID BLAST TUBE AND SAID COIL, AND EXPANSION CHAMBER INTERCONNECTING SAID COIL AND SAID BURNER NOZZLE, AND AN EXPANSION NOZZLE INTERNALLY OF SAID EXPANSION CHAMBER CONNECTED TO SAID CONDUIT PROVIDING INITIAL EXPANSION OF LIQUEFIED PETROLEUM GAS PASSING THERETHROUGH. 